Conversion of hydrocarbons



y 1942- I K. M. WATSON 2,282,273

CONVERSION OF HYDROCARBONS Filed June 7, 1940 v YQMJDW. 7/4/9011 Patented May 5, 1942 2.282.213 convansron' or nxnnocannons Kenneth M. Watson, Chicago, 111., asslgnor to I Universal Oil Products Company, Chicago, 111.,

a corporation of Delaware Application June 7, 1940, Serial No. 339,281 '1 Claims. (Cl. l9652) This invention relates to a process for converting hydrocarbon oil into valuable products including high antiknock gasoline. More particularly it relates to a combination of catalytic and non-catalytic cracking steps employing a powdered cracking catalyst for converting a distillate fraction. of hydrocarbon oil while cracking higher boiling oil and residual oil from both cracking steps in the non-catalytic cracking operation.

The charging stocks employed may be from any suitable" source including petroleum or'such stocks as shale oil, coal tar oil, etc. Two grades of gasoline are normally produced, one being a non-catalytic cracked gasoline of antiknock value suitable for use for ordinary motor fuel purposes and the other being a premium grade gasoline of high antiknock value.

In one specific embodiment the present invention comprises treating a distillate fraction of hydrocarbon oil with a powdered catalytic composite under catalytic cracking conditions of temperature and pressure, separating a portion of liquid reaction products containing catalyst in suspension, recycling a portion thereof, recovering a further. portion substantially free of catalyst, passing it to a non-catalytic cracking step hereinafter described, recovering the gasoline and gas from the catalytic cracking step, recycling a portion of the insufiiciently converted oil; separately treating a higher boiling hydrocarbon oil together with the portion of liquid reaction products previously mentioned, in a non-catalytic crackingstep under conditions of temperature and pressure adequate to produce substantial yields of gasoline, recycling a higher boiling portion of insufliciently converted oil to the non-catalytic cracking step, supplying an intermediate boiling fraction of insufficiently converted oil to the aforesaid catalytic cracking step,

and recovering the gasoline from said non-catalytic cracking step.

The invention is further understood by reference to the accompanying drawing which is diagrammatic and should not be interpreted as limiting the invention to the exact apparatus shown.

A distillate fraction of hydrocarbon oil such as gas oil, kerosene distillate of wax distillate, is introduced through line I, valve 2, pump 3 and valve 4 to coil 5 which is disposed in heater 6. A powdered catalytic agent is introduced from catalyst charger 1 through line 8 containing valve 9, pump l0 and valve II. The catalyst may be suspended in a portion of the charging stock,

may-be introduced in dry form, or may be suspended in a fraction of reaction products or other suitable carrying medium.

The catalyst may comprise any suitable cracking catalyst such as, for example, silica-alumina, silica-zirconia or silica-alumina-zirconia composites which may or may not have deposited thereon, promoting oxides such as those of chromium, molybdenum, tungsten, vanadium, titanium, thorium, etc. These composites are made in part by the separate or simultaneous precipitation of the components followed by washing and drying steps to substantially eliminate alkali metal ions from the composite. Another type of catalyst which may be useful comprises relatively inert carriers such as alumina, magnesia, titania, zinc oxide and the like having deposited thereon relatively minor portions of promoting oxides of chromium, molybdenum, tungsten, vanadium, etc. Still another ,type of catalyst which may be employed to advantage is the naturally-occurring earth type which may be further activated by treatment with chemicals including mineral acids. It should be borne in mind that the catalysts mentioned are not necessarily equivalent in their action.

The mixture'of oil and catalyst is heated in coil 5 to 'a temperature within the ran e of approximately 500-1200" F. and preferably within the range .of 650-1000 F. under pressure adequate to maintain a substantial portion of the oil boiling above the gasoline range, in liquid .phase. The heated mixture passes through line l2 containing valve l3 to catalytic reactor H which maycomprise a reaction chamber in which a liquid level is maintained. The. charge from line 12 is introduced to the catalytic reactor at a point below the surface of the liquid contained in said reactor in order to obtain additional conversion and likewise to keep the mixture agitated andprevent undue separation of the catalyst. The vaporous portion of reaction products including the gasoline and gas formed is removed through line l5 containing valve I6 to fractionator IT. Gasoline and gas are recovered through line I8, valve l9, condenser 20 and valve 2|, being collected in receiver 22. Gaseous reactants may be removed through line 23 and valve 24 to suitable absorption equipment not shown. These gases may be further treated by alkylation and/or polymerization steps to produce additional quantities of high antiknock gasoline. The gasoline may be withdrawn through line 25 and valve 26 to suitable stabilizers not shown and may be given such additional treatment as may be necessary to produce a finished product. The

asoline produced at this point normally of high antiknock value of the order of 75-80 octane number or higher and may be used -as such or may be used in blends with gasoline of low antiknockproperties to increase the octane number thereof. The portion of reactants boiling above the gasoline range is'withdrawrr from fractionator I! through line 21 and valve 28 to line 29 containing pump 30 and valve 3|, and being returned thus to the catalytic cracking step by way of line I. A liquid portion of reaction products from reactor is removed through line 32 and valve 33 to settler 34. Here sumcient time is allowed to permit substantial settling of the catalytic agent so that the catalyst concentrates,

in the lower portion of the settler. Oil containing a large quantity oi catalytic agent is withdrawn through line 35 containing valve 30, pump 31 and valve 38. The catalyst may be recovered therefrom and be regenerated by suitable treatment with an oxygen-containing gas whereby the hydrocarbonaceous-material is burned off.

A portion of the catalyst-oil concentrate may be passed through line 39 and valve 40 to catalytic reactor H in order to build up a high concentration of catalyst in the reactor. By means of this expedient it i's-possible to maintain a relatively high concentration of catalyst in the reaction zone without necessity for adding such large quantities to the charging stock initially. Thifs while from approximately 01-20% and preferably 0.l-5% of catalyst may be added with v passed through line 15 and yalve l8 joining wit line 29 ancl passing thence to line I. I Whentreating a Mid-Continent topped crude oil in the manner described, a yield of 59%.01

gasoline may be produced, of which a portion is a atalytically crackedproduct having an octane n mber of approximately 79, a further portion (of polymer gasoline of 83 octane number, the

remainder being -a non-catalytiqally cracked product with an octane number of '72. A silica-- alumina catalyst may be used for the catalytic portion .of this process at a temperature oi? approximately 1000 F. and a pressure of 50 pounds per square inch while using a temperature of 900 F. and a pressure of .250 pounds per square inch in the non-catalytic cracking step.

It should be borne in mind that the, above ex ample is given for illustrative purposes only and should not be interpreted as unduly limiting the invention to the exact conditions or catalysts employed.

I claim asmy invention: a

l. A process forthe conversion of hydrocarbon:

I oil which comprises catalytically cracking a rel-' the charging stock, much greater concentrations 1 of catalyst can be maintained in the reaction zone. The comparatively clear oil from the top of settler 34 is decanted through line 4|, valve 42, pump 43 and valve 44 joining with line 45. The oil is mixed with incoming hydrocarbon oil which may be any heavy hydrocarbon oil such as topped crude oil, reduced crude oil and the like, which is introduced through line 45, valve 46, pump 41 and valve 40, passing to coil 49 which is disposed in heater 50. Here themixture is treated under non-catalytic cracking conditions of temperature and pressure and passed through line 5| containing valve 52 to reaction chamber 53. The temperatures maintained are of the order of 850-1100 F. under pressures of approximately 100-1000 pounds per square inch. The

reaction products are passed' through line 54 7 controlled by valve 55, entering vaporizing chamber 56 at a reduced pressure within the range of approximately 25-200 pounds per square inch. A'

vGases are-withdrawn through line 61 and valve 68 andmay be treated as previously indicated for the catalyticallypro'duced gases. Gasoline is withdrawn through line 69 and valve 10 to be given such subsequent treatment as may be necessary to produce a finished motor fuel. The

v octane number of gasoline produced in this man ner normally ranges from approximately 65-75 and is suitable with or without the addition of tetraethyl lead for use as a motorfuel. High boiling reflux from fractionator BI is returned for further cracking by way of line H containin valve 12, pump 13 and valve 14, joining with line 1 45.- An intermediate boiling side cut maybe The atively light oil in the presence of a powdered cracking catalyst and under a pressure suflicient to maintain a substantial portion thereof in liquidphase, separating vapors from catalyst containing liquid reaction products, returning one portion of said catalyst containing liquid reaction product to the catalytic cracking, step. subjecting another portion of said liquid reaction products substantially free of catalyst to pyrolytic conversion together with a residual hydrocarbon oi, fractionating cracked vapors from the last me tioned conversion step to separate reflux condensate from the fractionated vapors, and supplying at least a portion of said reflux condensate to the'catlytic cracking step."

zirconia.

3. The process of claim 1 wherein the catalytic cracking step is carried out at'a temperature within the range of approximately soc-1200' F. I

and a pressure of 50-1000 pounds per square inch.

4. The process of claim 1 wherein the noncatalytic cracking step is conducted at a ,te'me perature within the range of approximately 850-1100 F. and a pressure'of approximately -1000 pounds per square inch.

5. A process for converting hydrocarbon oil into substantial yields of gasoline'and gas which comprises mixing a distillate fraction of said hyv drocarbon oil with a powdered catalytic agent.

"heating the'mixture under catalytic cracking conditions of temperature and pressure, passing the heated mixture to a reaction zone maintained at catalytic cracking conditions of temperature and under pressure sufficient to maintain a substantial quantity of oil boiling above the gasoline range in liquid phase, maintaining a liquid level in said reaction zone, passing a vaporous fraction oi reactants to a fractionation step,vrecovering gasoline and gas therefrom and recycling insufllciently converted oil for further conversion, withdrawing a. portion of the liquid reactants containing'catalyst in suspension from said reaction zone, subjecting the mixture to a settling step whereby the catalytic agent separates from one portion of the oil and concentrates in another portion, returning aportion of the catalyst-oil concentrate to said reaction zone thereby main:

2. The process of claim 1 wherein the cracking. catalyst is selected from the group consisting of; silica-alumina, silic'a-zirconia and silica-aluminatalnlng a relatively high concentration of catalyst therein, and removing a further portion of said' concentrate and recovering catalyst therefrom, supplying the portion of liquid'reactants which is substantially free of powdered catalyst together with residual hydrocarbon oil to a noncatalytic' cracking step, subjecting the reaction products therefrom to a fractionation step, recovering gasoline and gas, returning a portion of higher boiling insufliciently converted oil for further conversion in said non-catalytic cracking step and supplying a portion or intermediate boiling insumciently converted oil to the above,

one portion of said catalyst containing liquid re last mentioned conversion step to separate light and heavy reflux condensate from the tractionated vapors, supplying said light reflux condensate to the catalytic cracking step and the heavy reflux condensate to the pyrolytio cracking step.

7., A process for the conversion of hydrocarbon oil which comprises catalytically cracking a relatively light oil in the presence 02 a powdered cracking catalyst and under a pressure'sumcient to maintain a substantial portion thereof in liquid phase, separating vapors from catalyst containing liquid reaction products, supplying said catalyst containing liquid reaction products to a separator and therein concentrating the catalyst in one portion of the liquid reaction products, returning at least a portion-of the liquid reaction products containing the catalyst to the catalytic cracking st msubJectmg the liquid reaction product substantially free of catalyst to action products to the catalytic cracking step,

.bon oil, iractionating cracked vapors from the pyrolytic conversion together with a residual hydrocarbon oil, iractionating cracked vapors from the last mentioned conversion step to separate reflux condensate from the fractionated vapors and supplying at least a portion or said-reflux condensate to the catalytic cracking step.

KENNETH M. WATSON. 

